Add CalciteBinChartNullIT to CalciteNoPushdownIT suite

bin+chart with null values should also be tested with pushdown disabled.

Signed-off-by: Heng Qian <qianheng@amazon.com>

Author: qianheng-aws

integ-test/src/test/java/org/opensearch/sql/calcite/CalciteNoPushdownIT.java

@@ -25,6 +25,7 @@
   CalciteAddColTotalsCommandIT.class,
   CalciteConvertCommandIT.class,
   CalciteArrayFunctionIT.class,
+  CalciteBinChartNullIT.class,
   CalciteBinCommandIT.class,
   CalciteConvertTZFunctionIT.class,
   CalciteCsvFormatIT.class,